1. Field of the Invention
The present invention generally relates to automatic distribution equipment, and more particularly, to automatic distribution equipment which has a function of automatically connecting and disconnecting a subscriber and a switching system using a robot.
The present invention further relates to a connection-pin inserting-and-extracting apparatus which automatically forms a selected path by inserting a connection pin into a matrix switch board, and more particularly, to a connection-pin inserting-and-extracting apparatus including a connection-pin holding device which has sufficient connection-pin holing performance and has possibilities of miniaturization and cost reduction.
2. Description of the Related Art
(1) Automatic Distribution Equipment
First, a description will be given of prior-art automatic distribution equipment, by referring to FIG. 1 to FIG. 6.
FIG. 1 shows an illustration for explaining a typical function of a main distributing frame (MDF). The MDF is equipment for flexibly connecting a plurality of subscriber-side terminals and subscriber circuits located in a switching system. In the MDF, when a new subscriber is applied, the new subscriber is connected with the switching system, and when an address or a telephone number of the subscriber is changed, the connection between the subscriber and the switching system is changed. The connection changing may be carried out during an operation of the switching system. For efficient connection changing, the number of subscriber-side terminals (for example, X=3600 terminals) provided in the MDF is commonly larger than that of switching-system-side terminals (for example, Y=2100 terminals).
In the conventional MDF, as shown in FIG. 1, two terminal boards are provided. The subscriber and one terminal board are connected by a pair of cables, and the other terminal board and the switching system are also connected by a pair of cables. Further, the above two terminal boards are manually connected by a maintenance man using jumper wires to connect the subscriber and the switching system. Therefore, for the above-discussed connection work, a specially-skilled engineer is required. There is thus a problem that when the MDF is located in a remote area or an unmanned exchange office of an isolated island, it takes a long time to send the maintenance man, and the connection work for a variety of services, for example, telephone service, may not quickly be carried out. Further, since the above connection work is carried out mainly during the operation of the switching system, an errorless work is required. Accordingly, it takes a long time for that connection work. To overcome these problems, recently, an automatic MDF is developed, wherein a jumpering work is carried out by a robot.
FIG. 2 to FIG. 4 show a configuration example of a first prior-art automatic MDF. FIG. 2 shows a principle of the first prior-art automatic MDF. FIG. 3A to FIG. 3C show configurations of a prior-art matrix switch board and a connection pin used in the first prior-art automatic MDF. More specifically, FIG. 3A shows the configuration of the prior-art matrix switch board, FIG. 3B shows the configuration of the prior-art connection pin, and FIG. 3C shows an illustration indicating a condition in which the connection pin is inserted into the matrix switch board. FIG. 4 shows a configuration of the first prior-art automatic MDF.
As shown in FIG. 2, in the first prior-art automatic MDF, instead of the terminal board for the jumpering, a matrix switch board (MB) is provided. The matrix switch board is constructed with a multilayer-structure-type board, wherein a plurality of subscriber-side wires X and a plurality of switching-system-side wires Y are arranged in different layers so that the wires X, Y cross at substantially a right angle. At each cross point, a cross-point through hole is provided in the board, wherein by inserting a connection pin into the cross-point through hole, a desired subscriber-side wire X can be connected to a desired switching-system-side wire Y. In the automatic MDF, an inserting operation of the connection pin is automatically carried out by a robot.
When, for example, in one matrix switch board, 3600 terminals on the subscriber side and 2100 terminals on the switching system side are provided, 7.50-million cross-point holes need to be provided. In this case, robot control is subjected to a large amount of load. Therefore, in practical use, by arranging a plurality of small-sized matrix switch boards in a network-structure formation based on a given rule, substantially the same function is realized. In this method, the number of the cross-point holes may extremely be reduced.
Such a matrix switch board, as shown in FIG. 3A and FIG. 3C, is constructed with a printed wiring board having 4 conductive layers. In general, a connection between the subscriber and the switching system is wired by two wires designated A line and B line, and for high efficiency, the two wires are simultaneously connected. Therefore, the prior-art matrix switch board has the subscriber-side wires provided with the two layers (the A-line X layer and B-line X layer) and the switching-system-side wires provided with the two layers (the A-line Y layer and B-line Y layer), wherein the two groups of wires cross at substantially a right angle. At each cross point of these wires, a hole penetrating the printed wiring board is provided. In the prior-art matrix switch board, an interval of distance between adjacent holes in the printed wiring board is approximately 1.5 mm.
The prior-art connection pin has, as shown in FIG. 3B, two cylindrical connection springs a, b arranged in series in an axial direction. By inserting the connection pin into the cross-point hole of the matrix switch board, as shown in FIG. 3C, both connections between the subscriber-side A line and the switching-system-side A line and between the subscriber-side B line and the switching-system-side B line can simultaneously be wired. The prior-art connection pin has approximately an 8.7-mm length and is approximately 1.2 mm in diameter.
In the first prior-art automatic MDF, as shown in FIG. 4, a plurality of matrix switch boards 1 are dimensionally arranged so as to form one flat board. Two such flat boards are arranged on opposite sides of an apparatus 4 accommodating a robot 3 for inserting a connection pin 2. The robot 3 searches for a designated cross-point hole 5 in the flat board, and inserts the connection pin 2 into the designated cross-point hole 5. The connection pin 2 mounted in the robot 3 can turn in an opposite-side direction, and can also be inserted into the matrix switch board of the flat board arranged on the opposite side. Because the connection between the subscriber-side line and the switching-system-side line is carried out mainly during the operation of the switching system, one connection pin 2 is inserted for one transmission line to be connected. Since in the above-mentioned automatic MDF, a plurality of the matrix switch boards are dimensionally arranged, a width of the flat board may be several meters.
FIG. 5 shows a block diagram of the first prior-art automatic MDF shown in FIG. 4. The automatic MDF is constructed with a connection-path switching section 6 including the matrix switch board 1, the robot 3, and the robot-accommodating apparatus 4, a control section 7, a main storage device 8a, and a sub storage device 8b. Also, an operation terminal 9 is connected to the automatic MDF. In the automatic MDF, when an order to connect the subscriber-side line and the switching-system-side line is issued from the operation terminal 9, the control section 7 controls the connection-path switching section 6 according to contents of the main storage device 8a and the sub storage device 8b.
FIG. 6 shows a perspective view of a second prior-art automatic MDF. The second prior-art automatic MDF is disclosed in Japanese Laid-Open Patent Application No.3-104397. In the second prior-art automatic MDF, a plurality of matrix switch boards 1' are positioned in a vertical direction, and are arranged in a horizontal direction. A robot 3' which is movable in the vertical and horizontal directions is installed on the outside of the automatic MDF. Therefore, when the robot 3' inserts the connection pin into the matrix switch board 1' to carry out the connecting operation, the designated matrix switch board 1' having a designated cross-point hole is extracted out of the MDF, and in that condition, the connection pin is inserted into the cross-point hole.
In the second prior-art automatic MDF, because a plurality of matrix switch boards are three-dimensionally arranged, a large number of matrix switch boards may be accommodated.
However, the above-discussed prior-art automatic distribution equipment has the following problems.
In the first prior-art automatic distribution equipment, the matrix switch boards are dimensionally arranged. Therefore, a large number of matrix switch boards cannot be carried, and a carrying efficiency is degraded. Also, since a moving area of the robot is relatively wide, a function of searching for a position of the robot is complicated, and a size of the robot increases. Accordingly, there is a problem in that the robot may not efficiently be controlled, and the automatic distribution equipment becomes expensive.
In the second prior-art automatic distribution equipment, the matrix switch boards are three-dimensionally arranged, and the moving area of the robot is relatively narrow. However, to insert the connection pin, the matrix switch board needs to be extracted. Therefore, a long cable for connecting the extracted matrix switch board and a body of the equipment is necessary. This cable needs to include thousands of lines. Accordingly, there is a problem in that a mechanism of extracting the matrix switch board is significantly complicated.
Also, in the second prior-art automatic distribution equipment, a given period of time for extracting the matrix switch board is necessary. Namely, even if the robot is initially located adjacent to the designated matrix switch board, it takes the given period of time for extracting the matrix switch board before inserting the connection pin. Therefore, when many connection pins are inserted and extracted, an operation efficiency of the automatic MDF may be degraded.
Further, in the above-discussed first and second prior-art automatic distribution equipment, the matrix switch board including 4-layer wiring patterns is used. This matrix switch board is complex, and the manufacturing yield is degraded (i.e. low). There is a problem in that the matrix switch board is expensive.
Furthermore, the connection pin used in the first and second prior-art automatic distribution equipment needs to have two connection parts. Therefore, it is necessary to fix ring-type connection members to a plastic rod with maintaining a joint property. Therefore, there is thus a problem in that assembling of the connection pin is difficult, and, thus, cost thereof increases.
(2) Connection-Pin Inserting-and-Extracting Apparatus
Next, a description will be given of a connection-pin inserting-and-extracting apparatus, by referring to FIG. 7A to FIG. 8.
As discussed above, to establish a proper circuit by connecting and disconnecting conductive patterns at a given position in a telephone switching system, for example, there is a method of connecting a plurality of conductive patterns previously formed in the matrix switch board by inserting the connection pin into the cross-point hole.
For example, the matrix switch board has a plurality of conductive patterns which are arranged on opposite sides of the board so as to cross each other at the same coordinates. Also, by pressing and inserting the cylindrical connection pin having elasticity into a through hole formed in a cross point (cross-point hole), the connection between the conductive patterns may be carried out.
Further, when disconnecting the connected conductive patterns, the conductive patterns are disconnected by extracting the connection pin inserted in the through hole. Operations of inserting and extracting the connection pin are automatically carried out by a computer-controlled connection-pin inserting-and-extracting apparatus.
However, as shown in FIG. 3B, this connection pin is provided with the two cylindrical connection springs arranged in series in an axial direction. The two cylindrical connection springs are fixed to the body of a plastic rod while maintaining a joint property. Therefore, for forming the connection springs, a high quality and complex manufacturing technology is required. As a result, a cost of the connection pin increases, and there is thus a problem in that the cost of the connection-pin inserting-and-extracting apparatus may not be reduced.
FIG. 7A shows a cross-sectional view of a prior-art connection-pin holding device and FIG. 7B shows a bottom view of the prior-art connection-pin holding device. FIG. 8 shows an expanded illustration of a part of the prior-art connection-pin holding device shown in FIG. 7A.
A connection pin 20 used in the prior-art connection-pin holding device is constructed with a connection-pin body 21 and two cylindrical connection springs 22. The cylindrical connection springs 22 are fixed to the connection-pin body 21 made of a resin so as to have elasticity, and are electrically isolated from each other.
As shown in FIG. 7A, the prior-art connection-pin holding device includes a double-structure frame 10 having an outer frame 11 and an inner frame 12. In the inner frame 12, a front face thereof is supported through a pivot 13, and a back face, both-side faces, and a rear face are supported through a coil spring 14.
The inner frame 12 is provided with a holding mechanism 32 which has a plurality of swinging members 31 and holds the connection pin 20, and a driving mechanism 33. The swinging members 31 are arranged in a radial manner around the connection pin 20, and also, the middle part of each swinging member 31 is supported in a rotatable manner in the front face of the inner frame 12.
The driving mechanism 33 is installed inside the inner frame 12 perpendicularly to the matrix switch board, and is formed by an electromagnetic solenoid. Also, a plunger 34 is supported by the inner frame 12 in a slidable manner, and is pressed by a pressing coil spring 35 in a projected direction.
Each swinging member 31, whose middle part is supported in a rotatable manner, has a holding pawl 36 holding the connection pin 20 by contacting a side face of the connection pin 20 on a matrix-switch-board side of the swinging members 31. The plunger 34 is provided in a center of the holding mechanism 32, and has, in a top-end area, a member 37 relationally coupling with levers 38 formed on an opposite side of the holding pawls 36.
Before power is supplied to the driving mechanism 33, as shown in FIG. 8, the plunger 34 is projected to a given position by an operation of the pressing coil spring 35. At this time, respective levers 38 are pressed by the plunger 34 so as to rotate the swinging members 31. As a result, the holding pawls 36 holding the connection pin 20 are opened.
When the resin part of the connection pin 20 is inserted between the holding pawls 36, and when the power is supplied to the driving mechanism 33, the projected plunger 34 draws back. Accordingly, as shown in FIG. 7A and FIG. 7B, a plurality of the swinging members 31 simultaneously rotate. As a result, the holding pawls 36 contact the surrounding face of the connection pin 20 so as to hold the connection pin 20.
The outer frame 11 of the connection-pin holding device is fixed on a bracket (not shown) which is movable in X, Y, and Z axial directions. In this case, for example, the connection pin 20 may easily be inserted into the through hole by lowering the whole connection-pin holding device after the connection pin 20 is positioned above the through hole.
A plurality of the coil springs 14 are provided between the outer frame 11 and the inner frame 12 of the connection-pin holding device for compensating for position shift. When the inner frame 12 is raised up by a reaction of the connection-pin insertion, the inner frame 12 is separated from the pivots 13 on the outer frame 11 so as to compensate for the position shift.
When the connection pin previously inserted into the matrix switch board is extracted, the holding mechanism 32 is positioned at the connection pin 20, and the whole connection-pin holding device holding the connection pin is raised up. As a result, the connection pin is extracted from the matrix switch board.
However, since the prior-art connection-pin holding device has the swinging members 31 arranged in a radial manner around the connection pin, an external form of the holding mechanism 32 is relatively large. Further, since a plurality of the holding pawls 36 contact the surrounding face of the connection pin to hold the connection pin, high precision manufacturing techniques are required for forming the holding mechanism 32.
Since in the holding mechanism 32, a plurality of the holding pawls 36 contact the surrounding face of the connection pin to hold the connection pin, sufficient strength for holding the connection pin is required for the holding mechanism 32. Therefore, for the driving mechanism 33, there is a need for a large electromagnetic solenoid which can apply large strength to the swinging members 31 by drawing the plunger 34 against the pressing coil spring 35.
Further, in the prior-art connection-pin holding device, for compensating for the position shift, the frame 10 is constructed with the double structure of the outer frame 11 and the inner frame 12. Since a plurality of the coil springs 14 are provided between the outer frame 11 and the inner frame 12, there is a problem in that the external form of the connection-pin holding device is relatively large.